Near field communication (Near Field Communication, NFC) is a short-distance non-contact communications technology, and an operating frequency for the near field communication is 13.56 MHz.
With this technology, non-contact point-to-point data transmission and exchange are allowed between communications devices. The technology is combined with a mobile communications technology, so as to implement a plurality of service functions such as electronic payment, identity authentication, ticket purchase, and anti-spoofing.
A conventional NFC antenna designed to support an NFC function usually includes a circuit coil and a ferrite material. However, a conventional NFC antenna that is implemented in this manner has a large area, high costs, and increases a thickness of a communications device. Therefore, researchers are always devoted to proposing a new NFC antenna solution.
An antenna structure and an electronic device are provided in a patent CN 204760528U. The antenna structure may be configured to process a signal associated with a non-near field communication circuit. The antenna structure further has a part that forms a near field communication loop antenna to process a signal that is associated with a near field communication circuit. In the antenna structure, the near field communication circuit and the non-near field communication circuit are first connected to one node and then connected to an antenna resonant element by using a feeding path. In the antenna structure, because the non-near field communication circuit, the near field communication circuit, and the antenna resonant element are connected to a same node, a length of an antenna resonant element corresponding to the near field communication circuit is limited by a length of an antenna resonant element corresponding to the non-near field communication circuit, thereby affecting a signal radiation capability of the near field communication circuit. In addition, in the antenna structure, when the non-near field communication circuit operates on a plurality of frequency bands, at least two branches need to be separately designed, for example, a low frequency band branch and a high frequency band branch mentioned in the patent. The high frequency band branch shares no part with the antenna resonant element corresponding to the near field communication circuit. Therefore, if space of a terminal is limited, the antenna structure that is of relatively large size and that is provided in the patent may be used. In addition, in a scenario in which the antenna resonant element is formed on a metal frame of the terminal, a slot needs to be reserved between ground and an endpoint of the high frequency band branch and between the ground and an endpoint of the low frequency band branch. In this case, at least two non-metal straps need to be disposed on a metal frame of a communications device, and structural coherence is broken.
A patent US2015/0249485A1 discloses an electronic device that includes a near field antenna. The near field antenna uses an inverted F antenna structure, and a non-near field communication circuit and a near field communication circuit share the antenna structure. In the antenna structure, when the non-near field communication circuit operates on a plurality of frequency bands, at least two branches need to be separately designed, for example, a low frequency band branch and a high frequency band branch mentioned in the patent. The two branches are respectively formed on two sides of a connection node between a non-near field circuit and an antenna resonant element. When the antenna resonant element is a metal frame of a terminal, a slot needs to be reserved between ground and an endpoint of the high frequency band branch and between the ground and an endpoint of the low frequency band branch. In this case, at least two non-metal straps need to be disposed on the metal frame, and structural coherence is broken.